fix: add pytest-json-report dependency and improve error handling

- Add pytest-json-report to requirements-test.txt for JSON test output
- Improve error handling in test runner service to catch JSONDecodeError
  and fallback to parsing stdout when JSON report is unavailable

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

app/services/test_runner_service.py

@@ -96,14 +96,15 @@ class TestRunnerService:
                     report = json.load(f)
 
                 self._process_json_report(db, test_run, report)
-            except FileNotFoundError:
-                # Fallback to parsing stdout
+            except (FileNotFoundError, json.JSONDecodeError) as e:
+                # Fallback to parsing stdout if JSON report failed
+                logger.warning(f"JSON report unavailable ({e}), parsing stdout")
                 self._parse_pytest_output(test_run, result.stdout, result.stderr)
             finally:
                 # Clean up temp file
                 try:
                     Path(json_report_path).unlink()
-                except:
+                except Exception:
                     pass
 
             # Set final status